1. Field of the Invention
Embodiments of the invention generally relate to a grounding kit for a semiconductor processing chamber, and a semiconductor processing chamber having a grounding kit. More specifically, embodiments of the invention relate to a grounding kit capable of producing a uniform plasma in a physical vapor deposition chamber having asymmetrical RF power delivery.
2. Description of the Related Art
Physical vapor deposition (PVD), or sputtering, is one of the most commonly used processes in the fabrication of electronic devices. PVD is a plasma process performed in a vacuum chamber where a negatively biased target is exposed to a plasma of an inert gas having relatively heavy atoms (e.g., argon (Ar)) or a gas mixture comprising such inert gas. Bombardment of the target by ions of the inert gas results in ejection of atoms of the target material. The ejected atoms accumulate as a deposited film on a substrate placed on a substrate support pedestal disposed within the chamber. The support pedestal usually includes an electrostatic chuck (ESC) to support and retain substrates within the processing chamber during processing.
A grounding kit may be disposed in the chamber to create a return path for the RF power, which is used to create the plasma, to travel back to the RF power source. Due to process chamber complexity and size constraints, not all of the chamber components can be coaxially aligned with the substrate support pedestal. This offset of components can cause uniformity issues in the plasma created within the chamber. For instance, it has been found by the inventors that using a conventional grounding kit in a chamber having an offset RF power delivery site can cause the RF power to be distributed asymmetrically, especially at RF power frequencies greater than 13.56 MHz. Thus, the plasma created is distributed asymmetrically across the substrate being processed which can cause the substrate to be processed unevenly.
Although conventional grounding kit designs have a robust processing history at 13.56 MHz of RF power, processes performed using conventional kits at higher frequencies exhibit asymmetries beyond desirable limits. Therefore, there is a need in the art for an improved grounding kit.